Economic screening can be used in the early phases of power plant siting studies to identify and evaluate regional variations in plant construction and operating costs. The technique is applied after parts of the study region have been excluded by noneconomic criteria related to land use, technical feasibility, regulatory and environmental factors. Two case studies show how cost variables are analyzed, including make-up water supply, fuel transportation, transmission facilities and air quality. Contour cost maps show regional differential variations for each cost variable and for composite costs. The technique was very useful in screening large regions and identifying economically favorable siting areas.